Cable Replacement Method for Cable-Stayed Bridges Based on Sensitivity Analysis

Abstract

Cable replacement is one of the key technologies used in the successful operation and maintenance of cable-stayed bridges. Removing cables causes structural variations. Selecting a replacement method affects bridge safety during the cable replacement process. A sensitivity analysis was applied to assess the variations of force and deflection in the Sutong Bridge, China. Reasonable methods for both the quantity and position of replacing cables were provided; the bending strain energy changes induced by the cable removal were also analyzed to study the effects of different cable replacement sequences. Comparison of different cable removal schemes showed that both the induced cable force and beam stress change had their most significant influence on the nearest cables to those removed ones. Practically, the largest peak value of cable force increment appeared when removing the shortest cables. The peak value was practically identical with little apparent variation when removing one cable in the central span. The largest beam stress variation arose because of the longest cables (or their nearest neighbors) being removed. The maximum deflection of the tower top had a decreased tendency when the removed cable became short. The bending strain energy also decreased in a similar fashion. Based on the analysis results, replacing one cable from the side span and replacing four cables asymmetrically was recommended, and a replacement sequence running from the shortest cable to longest cable proved to be optimal.